That's what we are trying to make you understand: they already are in your QString but they have no visual representation. If you print the length of your string you'll see that it's not empty. You can process that string for whatever you need but you can't print anything readable.

For your information, the application read the weighing scale data through serial port. if i ran the application same application in windows machine, i will get the correct data .
Refer the attached image ( image url)
if i ran the application in the linux machine, i will get the escape sequence data only.
Refer image ( link url) .
Both are same application screen shot with different machine. I dint know, Why it is behave in linux environment. If it is uni coded character in linux, i need to covert the character similar to the windows output.

@aha_1980
The linux system is regular laptop and windows is another laptop.
The device is connected via USB( converter is used to covert the serial RS-232 to USB)
The external device is properly powered using separate power supply.

The issue was solved. Its related to linux OS problem. Its will work well with linux mint 19 OS. Before the earlier version of linux, the data received as encoded format only. In Linux mint 19, it will work fine in both cutecom as well as Qt application. Thanks for the support to solve the issue.